I found it so sad that Mario and Luigi recited Mario's "Nothing can hurt us as long as we're together" line from just before their seperation differently. Mario said it as "As long as we're together, everything is gonna be okay" when they reunited, which is not the exact same quote he made (he most likely wanted it to be the same). It seems like he forgot how he said it, especially with how much he was being tossed around. Luigi, however, when he was saving Mario's life and burning himself, said the same exact quote just the way Mario said it: "Nothing can hurt us as long as we're together". Luigi wasn't tossed around as much as Mario post-seperation, and the words of Mario stuck with Luigi as if that was the last words he was gonna hear from his brother.